Structure of the O-polysaccharide of Idiomarina zobellii KMM 231T containing two unusual amino sugars with the free amino group, 4-amino-4,6-dideoxy-d-glucose and 2-amino-2-deoxy-l-guluronic acid Original Research Article

Mild acid degradation of the lipopolysaccharide of the bacterium Idiomarina zobellii, type strain KMM 231T, with aq 2% HOAc at 100 °C, yielded an oligosaccharide, which represents one repeating unit of the O-polysaccharide. A polysaccharide was obtained by mild base degradation of the lipopolysaccharide. The following structure of the O-polysaccharide was elucidated by 1H and 13C NMR spectroscopy of the oligosaccharide and base-degraded lipopolysaccharide, including COSY, TOCSY, ROESY, 1H, 13C HSQC, HSQC-TOCSY and HMBC experiments: → 3)-α-d-Quip4N-(1 → 4)-α-d-GlcpA-(1 → 6)-α-d-GlcpNAc-(1 → 4)-α-l-GulpNA-(1 → 3)-β-d-FucpNAc-(1 → The O-polysaccharide is distinguished by the presence of two unusual amino sugars, 4-amino-4,6-dideoxy-d-glucose (d-Qui4N) and 2-amino-2-deoxy-l-guluronic acid (l-GulNA), both having the free amino group. The unexpectedly high acid lability of the glycosidic linkage of 2-acetamido-2,6-dideoxy-d-galactose (d-FucNAc) could be associated with the presence of a free amino group adjacent to the site of attachment of FucNAc to Qui4N.